Mechanical Heart Complex
by Orifiel
Summary: A cold and ruthless Lone Wanderer leads a solitary life in Rivet City after a series of ethically questionable decisions compels her to take a second look at what she has become… or what she has always been. Often at odds with the principled and stern Harkness, she comes to terms with the notion that between her and the android, she is the one more suited for a mechanical heart.


**Warning(s):** _Sexual content, graphic violence, possible references to past trauma, and some femslash. All that good stuff._

**Setting:** _Post-Fallout 3._

**A/N:** Sequel to "Reversal Red." Although it isn't necessary to read the first story to grasp the context of this one, spoilers abound for the fate of the relationship between Sienna Bordeaux (Lone Wanderer) and Freddie Gomez. This won't be as intense as "Reversal Red," but we'll get to see how the ending of it affected Sienna's mindset after she left Vault 101. I will state upfront that I never played the _Broken Steel_ DLC (as it took me five years on and off to actually finish _Fallout 3_). That being the case, this fic assumes that Sienna woke up in the Citadel's clinic after Project Purity, but gave the Brotherhood the finger and ran off without taking part in the events of _Broken Steel_. What a charming Lone Wanderer we're dealing with here…

x-x-x-x-x

**- I -**

**Ghost in a Prism**

Her boots plodded along the steel bridge leading to the looming, docked city, all metal structures and creaking walls. The bleak January sky stretched out above her in thick sheets of dark gray clouds. She bore the physical weight of her firearms and power armor, the mental weight of the choices that led her to this point, and the icy mindset that kept her from caring. Fatigue pulled at every muscle in her body as she clenched her teeth and continued dragging herself forward, the promise of a warm hotel bed too enticing to quit now.

In the distance, she spotted a familiar figure clad in the Rivet City security armor, Chinese assault rifle at the ready in his hands. Tension worked its way up her spine, but she proceeded toward him regardless. The events of the past few days—past few weeks, even—had taken their toll, and she needed to hole herself up somewhere safe for a while and let it all sink in. Nothing made sense anymore, and in a world that reviled her for her deeds over the span of five months in the Wasteland, she had reached her limit.

But despite all she'd gone through out here, the threads of her humanity had already begun fraying a long time ago.

x-x-x-x-x

"_If you can hear this, please stop looking for your dad and help stop mine. I changed the door password to my name. If you're hearing this, and if you still care enough to help me, you should remember it. Sienna, I… we need you. Please come back."_

_She listened to the repeating message, glazed vision roving over the dusk-colored plains. Dirt flew in gentle gusts over the screen of her Pip-Boy, which mapped the sound waves of Amata Almodovar's voice. She wiped the sweat from her brow with a grimy hand, allowing the nostalgic lilt to distract her from the chaotic thoughts plaguing her. But after a while, the inevitable ache only added to the turmoil._

_Her blue eyes drifted to the outer door of Vault 101, the worn and cracked wood beckoning from a mere thirty yards away. Two and a half months had passed since she'd crossed that threshold, and somehow she found herself back, a good deal smarter and with ten times the firepower. Still, she made no further move toward the entrance. She'd traveled back here on a whim and picked up the distress call, having walked all the way from the Citadel and past the ruins of Megaton to stand in this indecisive spot._

_Wisps of long black hair escaped the messy ponytail and fluttered over her shoulders as she cleared her constricting throat. Both a prison and a home, the Vault lived within her in the form of bitter memories scraping at the back of her skull. The environment that cultivated her upbringing had left a gaping wound in her chest, which festered to a gnawing absence of basic compassion. She dug her nails into the front of her armor toward her sternum, wondering if, upon reentering that Vault, she'd be able to find and retrieve the soul it had stolen._

_Her gaze narrowed as she weighed her options, the scale heavily biased against the perceived wrongs committed by the residents inside. Sneering expressions came to mind, followed by derisive remarks meant to criticize, put down, _humiliate_ her. The corridors echoed with their whispers, bearing thinly veiled scorn for the girl who had never fit in. Her father's status provided the only buffer from outright ridicule, and once he had fled, she'd had little choice but to follow, lest she invite the full force of 101's wrath upon her head._

_Such hardships in such a small community, all because she'd wanted a woman instead of a man by her side._

_She took a step forward as Amata's pleading words persisted around her. At one point in time, she would have done anything Amata asked in return for her favor and a chance at having her feelings reciprocated. A foolish wish, which ended in a painful separation, and the severed bond never had a chance to mend. Some others supported her after Amata's rejection, but the Overseer's spiteful sheep outnumbered them. She ultimately withdrew into herself and rode out the storm of her adolescence in cold isolation._

_Until Freddie Gomez came along._

_Her lips fell into a hard line as she tore her sight away from the Vault entrance. Freddie. Words still eluded her whenever she tried to describe the progression of that relationship. It was all a plethora of guilt and desire and… just so much wasted potential. And although a hidden part of her admitted that something there still lingered, the blame locked it away along with the last vestiges of her civility._

_She shut off the radio frequency on her Pip-Boy, features blank to mask the ire churning under the surface. The same place that housed her past suffering now dared to ask for her help, and she would have laughed at the irony if her father's recent death hadn't taken more of her with him. She felt whittled down to nothing, yet everyone from all directions saw her as the answer, like some kind of deus ex machina; a ghost in a prism._

_A vindictive scoff left her mouth as she pivoted on her heel, and she drew her hunting rifle to prepare for the dangers of the encroaching night on her long trek back to the Citadel. The final stages of Project Purity awaited. She had no time to rescue a society that lacked redeeming qualities. Closure, amends… these things held no appeal for her. She'd washed her hands of Vault 101. Those people who drove her out now needed her? Too bad. _

_Let them rot._

x-x-x-x-x

She met the security chief's steady look with a steely one as she reached the end of the bridge and came to a halt in front of him, panting from exertion. He appeared as well-groomed as ever, clean-shaven, and with his neat chestnut hair combed to the side. Strict brown eyes searched her face while his frown deepened, the disapproval in his expression enough to grate on her nerves.

"Sienna Bordeaux. What brings you back to Rivet City?" he demanded as he lowered the assault rifle.

"A3-21," she drawled, concealing a smirk when he stiffened. "What's with the interrogation? New safety precaution to screen out other suspected SRB members?"

"This is the last time I'm going tell you, kid. Either call me Harkness and stop bringing that up or get the hell off my boat," he snapped, his voice growing gruffer at the mention of the Synth Retention Bureau.

She issued a weary sigh and shifted the heavy pack strapped over her armor. "Relax. I won't say anything in front of other people." Several beats of strained silence went by before she added, "Now move so I can pass out at the Weatherly."

He pinned her with a dubious stare. "Looking to bunk in the hotel, huh? Did your Tenpenny suite lose its flavor or something?"

Sienna's gaze went skyward as she fought the urge to shove past him. Her half-healed injuries throbbed under the bandages wrapped by the Brotherhood medics, having been exacerbated during her violent final departure from the Citadel. She'd had enough of the incessant missions, the constant expectations of following others' linear to-do lists. Her agenda now consisted of laying low and recuperating, but of course this troublesome, wary man insisted on making himself an obstacle.

"It's all the way across the map, and I just got back on my feet after making Project Purity a success," she told him tiredly. _So you should be rolling out the red carpet for the person who brought purified water to the Capital Wasteland._

Harkness's jaw tightened. "From what I've heard on the radio, the real hero is a late Brotherhood Sentinel. Not you."

She swore under her breath. _Goddamn Three Dog._

He studied her for a moment, taking in her bedraggled state. She'd never liked his perpetual analyzing, the way he always breathed down her neck, as if he had wired his own system to track her every move. One incident involving an assisted suicide of a hopeless, elderly man, and Harkness had swooped down on her like a reenactment of the Great War. Despite all the favors she had done for other Rivet City residents, he had targeted her for life.

Even now, several weeks after the fact, he still held onto that grudge. She estimated three minutes tops before her knees gave out and sent her crumpling to the ground in a graceless heap. Patience ebbed and gave way to consternation as a spell of dizziness swept over her.

"Is that what this is about? What, you only let heroes in now?" Sienna asked.

Harkness stepped closer, eyeing her harshly. "This is about me making sure you won't be a problem before I let you back into this city," he growled. "Even if you helped with Project Purity, you're on thin ice as it is."

She froze at those last few words, catching the flicker of perplexity cross his features when she pierced him with a fierce glower. _Thin ice._ An image of another man, much younger, filled her vision and dispelled the lethargy in her bones at once. A wave of unwanted emotions followed, breaking free of their bindings to race across her working memory. Grief. Shame. Remorse. These unacknowledged things clawed for recognition, and she forcibly pushed them back, dismissing their existence once again. Tense minutes passed. She drew in a sharp breath, angry, slighted, and just a little uneasy.

No matter the distance or length of time, the Vault still lived within her.

Harkness couldn't have known the can of worms he'd opened with that latter sentence, but he found himself backing up and brandishing his assault rifle when she invaded his personal space.

"You know, I was this close to handing your synthetic ass over to Zimmer," Sienna hissed in a low, threatening pitch while jabbing the front of his vest with her index finger. She stood close enough to see the nicks and scars on the skin of his face, every realistic crease and pore that disguised the true construction beneath. "But I didn't. So at least give me that."

He glared down at her, bringing up a hand to shove her away. She staggered and regained her footing, never breaking their eye contact. The temperature plummeted in the space between them, and she witnessed the way he seemed to wrestle with his own prejudice against her. It was a prejudice built on justified ground, but it also gave her little room to prove her willingness to reform. Or, at least, her willingness to keep to herself and steer clear of others.

Finally, Harkness barked, "Am I going to regret letting you in?"

"No."

The single word held the resonating sincerity of an exhausted spirit just wanting to rest. Another few seconds ticked by before he stepped aside and gestured her forward. Although he still appeared unhappy about granting her access, his reservations switched to surprise when she pushed a plasma rifle into his arms as she trudged past. He balanced it over the firearm he already carried, remarking out loud that it had been the one he'd given her a while ago.

"You can have that back, by the way," she declared. "Never felt right carrying a piece of you with me, android."

She made it to the marketplace entrance before he spoke.

"Sienna," he called, slinging the plasma rifle over his shoulder. "Maybe you should reconsider which of us is the human and which of us is the machine here."

She paused in mid-step, but proceeded inside without answering. No point dwelling on something she already knew.

Her body was flesh, her heart mechanical.

x-x-x-x-x

**A/N:** Some subtle references to events and dialogue from "Reversal Red" will appear (such as the "thin ice" line), though these smaller things won't have that much of an impact on the story. Sienna is sort of a character study for me since I'm learning my way around developing a personality from scratch, as opposed to developing an established canon character's personality. It's definitely a challenge—especially since she's a stone cold bitch—but I always like tackling new things in writing, so hopefully I handle her characterization well throughout. Constructive criticism, questions, and any other comments are much appreciated!


End file.
